Recon, no matter how old my GSP was, he puked... motion sickness was something of him he didnt like. even my wife went 7 block drive and back, puked no matter what. even puked when riding on the ATV.
again i dont know if he would grow out of it. however, my cat, when he goes for a ride, if i DONT feed him in the morning and goes, he does fine, if he does eat, then he pukes.
i would try to do what was suggested on the first page of trying to find something he can take that would help. dont give him two things at once to see what works. try pespmo bismo and see, if not, go to a vet and see what they can give you to help.
eventually, he should grow out of it.. i would assume they do.